HAVANA U.S. President Barack Obama and President Raul Castro held historic talks in Havana on Monday, discussing enduring disagreements over Cuba's human rights record and Washington's trade embargo as the two countries took another stride away from Cold War-era animosity.

Obama arrived in Cuba on Sunday for the first visit by a U.S. president in almost 90 years, achieving a goal for his final year in office that became possible after secret talks led to a 2014 agreement to normalize relations.

The opening ended decades of U.S. efforts to force Cuba to change through isolation. But Obama is under pressure from critics at home to push Castro's government to allow political dissent and to further open its Soviet-style state-run economy.

Obama began his first full day in the symbolic heart of Cuba's Communist system, starting in Revolution Square, where for decades Raul Castro's brother, Fidel Castro, led million-strong rallies against the evils of U.S. "imperialism."

"It is a great honor to pay tribute to Jose Marti, who gave his life for independence of his homeland. His passion for liberty, freedom, and self-determination lives on in the Cuban people today," Obama wrote in a guest book there.

Marti was a 19th century poet and writer whose activism helped spur Cuba's freedom from Spain and whose legacy was later adopted by Fidel Castro's revolutionaries as a symbol of anti-imperialism.

Obama then moved on to the adjacent Palace of the Revolution, where the Castros have led Cuba's resistance to U.S. pressure going back decades. A U.S. presidential visit to the inner sanctum of Cuban power was unthinkable before Obama and Raul Castro's rapprochement in December 2014.

Obama and Castro have met three times before, but Monday's meeting was set to be the most substantial as the two men move on from last year's restoration of diplomatic ties and attempt to rebuild the bilateral relationship.

Inside the palace, Castro and Obama stood shoulder to shoulder while a military band played the Cuban national anthem and then the U.S. anthem, and then they walked past a military honor guard.

Castro was all smiles as he greeted Obama. But he has said Cuba will not waver from its 57-year-old revolution. Government officials say the United States needs to end its economic embargo and return the Guantanamo Bay naval base to Cuba before the two countries can enjoy normal relations.

Monday's formal ceremony contrasted with Obama's lower key arrival on Air Force One in Havana on Sunday. Castro did not meet the plane and there were no military honors.

INTERNET, POLITICAL DISSENT

Critics of Obama have accused him of rewarding Havana prematurely.

"Freedom can come to Cuba, but it cannot happen by enriching and empowering the dictatorship," Republican presidential candidate Ted Cruz, a Cuban-American U.S. senator from Texas, said in a tweet.

Obama is expected to encourage more economic reforms and greater access to the Internet for Cubans during the talks.

Ahead of his meeting with Castro, Obama announced a deal that Google has reached with the island.

"One of the things that we'll be announcing here is that Google has a deal to start setting up more Wi-Fi and broadband access on the island," Obama told ABC News in an interview that aired on Monday. He gave no other details, and representatives for Google could not be immediately reached.

His administration hopes changes might also come at a Communist Party congress next month, but doubts any political opening will be forthcoming.

Cuban police backed by hundreds of shouting pro-government demonstrators broke up a Ladies in White march on Sunday, detaining dozens of people just hours before Obama landed.

Obama has urged Congress to rescind the 54-year-old embargo but has been rejected by the Republican leadership. He now has both Democratic and Republican elected officials with him on his Cuba trip and hopes Congress may act after the Nov. 8 presidential election.

Asked about the potential for U.S. companies to lose out to other countries in the Cuban market, Obama told ABC: "There's no doubt that we still have some work to do, and part of that is bringing an end to the embargo that is currently in place." While it may not happen during his final year in office given the U.S. presidential election, "it is inevitable," he added.

Thwarted by Congress on the embargo, Obama has instead used his executive authority to take a series of steps loosening restrictions on trade and travel with the Caribbean island.

Cuba has praised those measures but Castro will likely use Monday's meeting to press Obama to go further.

"We think the U.S. government can take more steps to send clear and direct signals in this direction," Foreign Trade Minister Rodrigo Malmierca told reporters on Sunday.

The U.S. Treasury Department on Sunday granted hotel group Marriott permission to do business in Cuba, adding to the list of U.S. companies allowed to sidestep the embargo. Marriott said it wants to build a hotel on the island but does not yet have a deal.

Obama and Castro met for half an hour during a regional summit in Panama last April and they also had a brief encounter at Nelson Mandela's funeral in 2013 and at longer meeting at the U.N. General Assembly last September.

Besides meeting Castro, Obama also plans to visit a state-owned micro brewery and attend a state dinner on Monday. On Tuesday, he will deliver a speech on live Cuban television and attend an exhibition game between Major League Baseball's Tampa Bay Rays and Cuba's national team.